The milestone episode, airing in November, will also have "musical-ish" elements.

Supernatural had a rollicking good time opening Hall H on the final day of Comic-Con.

The season-nine finale saw Dean Winchester turned into a demon and the consequences of that change up in the air. "It has an enormous effect on the season and on the brothers," said executive producer Jeremy Carver of the introduction of Demon Dean. "It's part of the opening episodes. Sam, in particular, [digs into] how to rescue his brother. Dean ... struggles with what exactly that means."

"Myself and the other writers are excited most of all that the idea of these brothers questioning who the real monster is," added Carver. "It's great and it's exciting and emotional and fun."

For Jensen Ackles, who directed the third episode of the season (more on that later), the shift in Dean's character was a welcomed change. "This is actually Dean's soul that is twisted. It was interesting trying to make it a different character but at the same time, be the same character — but twisted and demonic," he said. Hall H was treated to a special first look at the third episode of Supernatural, directed by Ackles, whichis the first time Dean confronts Sam after he's been turned into a demon.

A fading Castiel, meanwhile, will spend a good portion of his time "helping Dean getting patched up" instead of "recovering his own powers," said Misha Collins.

The long-running drama hits its 200th milestone episode in November and Carver promised that the hour will be "a love letter to the fans" of The CW show and have "musical-ish" elements. "It's wonderful to thank you guys on screen," said Jared Padalecki. The premiere, in fact, will also have a heavy dose of music with singing and "rump-shaking," Carver teased. "Apparently Demon Dean likes to karaoke, or does he?" Ackles joked.

Supernatural has famous fans and one of them is William Shatner, who has live-tweeted episodes of the show. When asked about the chances of Shatner appearing, Collins was all for the idea. "He'd have to audition with everyone else," he joked.

Among the other highlights were the annual screening of the previous season's gag reel and a surprise appearance by Osric Chau, who played Kevin Tran.